@article{pakpinyo_ley_barnes_vaillancourt_guy_2003, title={Enhancement of enteropathogenic Escherichia coli pathogenicity in young turkeys by concurrent turkey coronavirus infection}, volume={47}, ISSN={["0005-2086"]}, DOI={10.1637/0005-2086(2003)047[0396:EOEECP]2.0.CO;2}, abstractNote={Abstract In a previous study, turkey coronavirus (TCV) and enteropathogenic Escherichia coli (EPEC) were shown to synergistically interact in young turkeys coinfected with these agents. In that study, inapparent or mild disease was observed in turkeys inoculated with only TCV or EPEC, whereas severe growth depression and high mortality were observed in dually inoculated turkeys. The purpose of the present study was to further evaluate the pathogenesis of combined TCV/EPEC infection in young turkeys and determine the role of these agents in the observed synergistic interaction. Experiments were conducted to determine 1) effect of EPEC dose, with and without concurrent TCV infection, and 2) effect of TCV exposure, before and after EPEC exposure, on development of clinical disease. Additionally, the effect of combined infection on TCV and EPEC shedding was determined. No clinical sign of disease and no attaching and effacing (AE) lesions characteristic of EPEC were observed in turkeys inoculated with only EPEC isolate R98/5, even when turkeys were inoculated with 1010 colony forming units (CFU) EPEC (high dose exposure). Only mild growth depression was observed in turkeys inoculated with only TCV; however, turkeys inoculated with both TCV and 104 CFU EPEC (low dose exposure) developed severe disease characterized by high mortality, marked growth depression, and AE lesions. Inoculation of turkeys with TCV 7 days prior to EPEC inoculation produced more severe disease (numerically greater mortality, significantly lower survival probability [P < 0.05], increased frequency of AE lesions) than that observed in turkeys inoculated with EPEC prior to TCV or simultaneously inoculated with these agents. Coinfection of turkeys with TCV and EPEC resulted in significantly increased (P < 0.05) shedding of EPEC, but not TCV, in intestinal contents of turkeys. These findings indicate that TCV infection predisposes young turkeys to secondary EPEC infection and potentiates the expression of EPEC pathogenicity in young turkeys.}, number={2}, journal={AVIAN DISEASES}, author={Pakpinyo, S and Ley, DH and Barnes, HJ and Vaillancourt, JP and Guy, JS}, year={2003}, pages={396–405} }
 @article{guy_smith_breslin_pakpinyo_2002, title={Development of a competitive enzyme-linked immunosorbent assay for detection of turkey coronavirus antibodies}, volume={46}, ISSN={["0005-2086"]}, DOI={10.1637/0005-2086(2002)046[0334:DOACEL]2.0.CO;2}, abstractNote={SUMMARY. A competitive enzyme-linked immunosorbent assay (cELISA) was developed for detection of turkey coronavirus (TCV) antibodies. The cELISA utilized a recombinant baculovirus (Autographa californica nuclear polyhedrosis virus)-expressed TCV nucleocapsid (N) protein and biotin-labeled TCV N protein-specific monoclonal antibody. Sensitivity and specificity of the cELISA for detection of TCV antibodies were determined by comparison with the indirect fluorescent antibody test (IFAT) with 1269 reference, experimentally derived, and field-origin sera. Sera with discordant cELISA and IFAT results were further evaluated by western immunoblot analyses. The cELISA detected antibodies specific for TCV and infectious bronchitis virus, a closely related coronavirus, but did not detect antibodies specific for other avian viruses. A high degree of concordance was observed between the cELISA and IFAT; sensitivity and specificity of the cELISA relative to IFAT were 92.9% and 96.2%, respectively. Western immunoblot analyses provided additional evidence of cELISA specificity. The findings indicate that the cELISA is a rapid, sensitive, and specific serologic test for detection of TCV antibodies in turkeys.}, number={2}, journal={AVIAN DISEASES}, author={Guy, JS and Smith, LG and Breslin, JJ and Pakpinyo, S}, year={2002}, pages={334–341} }
 @article{pakpinyo_ley_barnes_vaillancourt_guy_2002, title={Prevalence of Enteropathogenic Escherichia coli in Naturally Occurring Cases of Poult Enteritis–Mortality Syndrome}, volume={46}, ISSN={0005-2086 1938-4351}, url={http://dx.doi.org/10.1637/0005-2086(2002)046[0360:poeeci]2.0.co;2}, DOI={10.1637/0005-2086(2002)046[0360:POEECI]2.0.CO;2}, abstractNote={SUMMARY. Enteropathogenic Escherichia coli (EPEC) previously were identified in poult enteritis–mortality syndrome (PEMS)-affected turkeys and associated as a cause of this disease. In the present study, the prevalence of EPEC in PEMS-affected turkeys was examined retrospectively with archived tissues and intestinal contents collected from 12 PEMS-affected turkey flocks in 1998. Formalin-fixed intestinal tissues were examined by light and electron microscopy for attaching and effacing (AE) lesions characteristic of EPEC, and frozen (−75 C) intestinal contents were examined for presence of EPEC. Escherichia coli isolates were characterized on the basis of epithelial cell attachment, fluorescent actin staining (FAS) test, and presence of E. coli attaching/effacing (EAE), shigalike toxin (SLT) type I, SLT II, and bundle-forming pilus (BFP) genes by polymerase chain reaction procedures. EPEC isolates were examined for pathogenicity and ability to induce AE lesions in experimentally inoculated young turkeys. AE lesions were identified by light microscopy in Giemsa-stained intestines from 7 of 12 PEMS-affected turkey flocks. Lesions consisted of bacterial microcolonies attached to epithelial surfaces with epithelial degeneration at sites of attachment and inflammatory infiltration of the lamina propria. Electron microscopy confirmed the identity of AE lesions in six of seven flocks determined to have AE lesions by light microscopy. EPEC were identified in 4 of 12 flocks on the basis of the presence of EAE genes and absence of SLT I and SLT II genes; all isolates lacked BFP genes. EPEC isolates produced AE lesions and variable mortality in turkeys coinfected with turkey coronavirus. In total, EPEC were associated with 10 of 12 (83%) naturally occurring PEMS cases on the basis of identification of AE lesions and/or EPEC isolates. These findings provide additional evidence suggesting a possible role for EPEC in the pathogenesis of PEMS.}, number={2}, journal={Avian Diseases}, publisher={American Association of Avian Pathologists (AAAP)}, author={Pakpinyo, S. and Ley, D. H. and Barnes, H. J. and Vaillancourt, J. P. and Guy, J. S.}, year={2002}, month={Apr}, pages={360–369} }